The Islamic State of Iraq and Syria (ISIS) is one of the strongest militant groups in the Middle East. Starting from the establishment of Al-Qaeda in Iraq, ISIS began to principally eradicate the position in the west and instill Sunni Islamic law to find the caliphate state reading to Syria . In their journey ISIS chose to recruit adult jihadists to help get their vision, but also represented a problem in supporting terrorism so far against the Islamic jihadis ISIS is massively recruiting children as child soldiers or jihadists to extend the length. By the Recruitment Theory of the Child Army, this paper attempts to explain how the process of recruiting child soldiers in ISIS circles.